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Posted to commits@camel.apache.org by bu...@apache.org on 2015/09/22 21:20:09 UTC
svn commit: r966394 [2/2] - in /websites/production/camel/content:
book-in-one-page.html book-pattern-appendix.html cache/main.pageCache
polling-consumer.html
Modified: websites/production/camel/content/book-pattern-appendix.html
==============================================================================
--- websites/production/camel/content/book-pattern-appendix.html (original)
+++ websites/production/camel/content/book-pattern-appendix.html Tue Sep 22 19:20:06 2015
@@ -2731,7 +2731,16 @@ from("seda:a").throttle(3).tim
</div></div><p>So the above example will throttle messages all messages received on <strong>seda:a</strong> before being sent to <strong>mock:result</strong> ensuring that a maximum of 3 messages are sent in any 10 second window.</p><p>Note that since <code>timePeriodMillis</code> defaults to 1000 milliseconds, just setting the <code>maximumRequestsPerPeriod</code> has the effect of setting the maximum number of requests per second. So to throttle requests at 100 requests per second between two endpoints, it would look more like this...</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="brush: java; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[from("seda:a").throttle(100).to("seda:b");
]]></script>
-</div></div><p>For further examples of this pattern in use you could look at the <a shape="rect" class="external-link" href="http://svn.apache.org/viewvc/camel/trunk/camel-core/src/test/java/org/apache/camel/processor/ThrottlerTest.java?view=markup">junit test case</a></p><p><strong>Using the <a shape="rect" href="spring-xml-extensions.html">Spring XML Extensions</a></strong></p><h4 id="BookPatternAppendix-Camel2.7.xorolder">Camel 2.7.x or older</h4><div class="error"><span class="error">Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20</span> </div><h4 id="BookPatternAppendix-Camel2.8onwards">Camel 2.8 onwards</h4><p>In Camel 2.8 onwards you must set the maximum period as an <a shape="rect" href="expression.html">Expression</a> as shown below where we use a <a shape="rect" href="constant.html">Constant</a> expression:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+</div></div><p>For further examples of this pattern in use you could look at the <a shape="rect" class="external-link" href="http://svn.apache.org/viewvc/camel/trunk/camel-core/src/test/java/org/apache/camel/processor/ThrottlerTest.java?view=markup">junit test case</a></p><p><strong>Using the <a shape="rect" href="spring-xml-extensions.html">Spring XML Extensions</a></strong></p><h4 id="BookPatternAppendix-Camel2.7.xorolder">Camel 2.7.x or older</h4><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="brush: xml; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[
+<route>
+ <from uri="seda:a" />
+ <throttle maximumRequestsPerPeriod="3" timePeriodMillis="10000">
+ <to uri="mock:result" />
+ </throttle>
+</route>
+]]></script>
+</div></div><h4 id="BookPatternAppendix-Camel2.8onwards">Camel 2.8 onwards</h4><p>In Camel 2.8 onwards you must set the maximum period as an <a shape="rect" href="expression.html">Expression</a> as shown below where we use a <a shape="rect" href="constant.html">Constant</a> expression:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="brush: xml; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[
<route>
<from uri="seda:a"/>
@@ -4014,7 +4023,52 @@ public class SpringConsumerTemplateTest
}
]]></script>
-</div></div><h4 id="BookPatternAppendix-Timerbasedpollingconsumer">Timer based polling consumer</h4><p>In this sample we use a <a shape="rect" href="timer.html">Timer</a> to schedule a route to be started every 5th second and invoke our bean <strong>MyCoolBean</strong> where we implement the business logic for the <a shape="rect" href="polling-consumer.html">Polling Consumer</a>. Here we want to consume all messages from a JMS queue, process the message and send them to the next queue.</p><p>First we setup our route as:</p><div class="error"><span class="error">Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20</span> </div>And then we have out logic in our bean:<div class="error"><span class="error">Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20</span> </div><h3 id="BookPatternAppendix-ScheduledPollComponents">Scheduled Poll Components</h3><p>Quite a few inbound Camel endpoints use a scheduled poll pa
ttern to receive messages and push them through the Camel processing routes. That is to say externally from the client the endpoint appears to use an <a shape="rect" href="event-driven-consumer.html">Event Driven Consumer</a> but internally a scheduled poll is used to monitor some kind of state or resource and then fire message exchanges.</p><p>Since this a such a common pattern, polling components can extend the <a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a> base class which makes it simpler to implement this pattern.</p><p>There is also the <a shape="rect" href="quartz.html">Quartz Component</a> which provides scheduled delivery of messages using the Quartz enterprise scheduler.</p><p>For more details see:</p><ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/PollingConsumer.html
">PollingConsumer</a></li><li>Scheduled Polling Components<ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a></li><li><a shape="rect" href="scheduler.html">Scheduler</a></li><li><a shape="rect" href="atom.html">Atom</a></li><li><a shape="rect" href="beanstalk.html">Beanstalk</a></li><li><a shape="rect" href="file2.html">File</a></li><li><a shape="rect" href="ftp2.html">FTP</a></li><li><a shape="rect" href="hbase.html">hbase</a></li><li><a shape="rect" href="ibatis.html">iBATIS</a></li><li><a shape="rect" href="jpa.html">JPA</a></li><li><a shape="rect" href="mail.html">Mail</a></li><li><a shape="rect" href="mybatis.html">MyBatis</a></li><li><a shape="rect" href="quartz.html">Quartz</a></li><li><a shape="rect" href="snmp.html">SNMP</a></li><li><a shape="rect" href="aws-s3.html">AWS-S3</a></li><li><a shape="rect" href="aws-sqs.html">AWS-SQS</a></li></ul><
/li></ul><h3 id="BookPatternAppendix-ScheduledPollConsumerOptions">ScheduledPollConsumer Options</h3><p>The ScheduledPollConsumer supports the following options:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Option</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>pollStrategy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"> </td><td colspan="1" rowspan="1" class="confluenceTd"><p>A pluggable <code>org.apache.camel.PollingConsumerPollingStrategy</code> allowing you to provide your custom implementation to control error handling usually occurred during the <code>poll</code> operation <strong>before</strong> an <a shape="rect" href="exchange.html">Exchange</a> have been created and being routed
in Camel. In other words the error occurred while the polling was gathering information, for instance access to a file network failed so Camel cannot access it to scan for files. The default implementation will log the caused exception at <code>WARN</code> level and ignore it.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>sendEmptyMessageWhenIdle</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>startScheduler</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Whether the scheduler should be auto started.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>initialDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the first poll starts.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>delay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>500</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the next poll.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>useFixedDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Controls if fixed delay or fixed rate is used. See <a shape="rect" class="external-link" href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/ScheduledExecutorService.html" rel="nofollow">ScheduledExecutorService</a> in JDK for details. In <strong>Camel 2.7.x</strong>
or older the default value is <code>false</code>. From <strong>Camel 2.8</strong> onwards the default value is <code>true</code>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>timeUnit</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TimeUnit.MILLISECONDS</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>time unit for <code>initialDelay</code> and <code>delay</code> options.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>runLoggingLevel</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TRACE</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.8:</strong> The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduledExecutorService</code></p></td><td colspan="1" rowspan="1" class="confluenceT
d"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10:</strong> Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool. This option allows you to share a thread pool among multiple consumers.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>greedy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10.6/2.11.1:</strong> If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> Allow to plugin a
custom <code>org.apache.camel.spi.ScheduledPollConsumerScheduler</code> to use as the scheduler for firing when the polling consumer runs. The default implementation uses the <code>ScheduledExecutorService</code> and there is a <a shape="rect" href="quartz2.html">Quartz2</a>, and <a shape="rect" href="spring.html">Spring</a> based which supports CRON expressions. <strong>Notice:</strong> If using a custom scheduler then the options for <code>initialDelay</code>, <code>useFixedDelay</code>, <code>timeUnit</code>, and <code>scheduledExecutorService</code> may not be in use. Use the text <code>quartz2</code> to refer to use the <a shape="rect" href="quartz2.html">Quartz2</a> scheduler; and use the text <code>spring</code> to use the <a shape="rect" href="spring.html">Spring</a> based; and use the text <code>#myScheduler</code> to refer to a custom scheduler by its id in the <a shape="rect" href="registry.html">Registry</a>. See <a shape="rect" href="quartz2.html">Quartz2</a> page for
an example.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler.xxx</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To configure additional properties when using a custom <code>scheduler</code> or any of the <a shape="rect" href="quartz2.html">Quartz2</a>, <a shape="rect" href="spring.html">Spring</a> based scheduler.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffMultiplier</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use th
en <code>backoffIdleThreshold</code> and/or <code>backoffErrorThreshold</code> must also be configured.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffIdleThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent idle polls that should happen before the <code>backoffMultipler</code> should kick-in.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffErrorThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent error polls (failed due some error) that should happen before the <code>backoffMultipler</code> should kick-in.</p></td></tr></tbody></table></div></div><h3 id="BookPatternAppendix-Usingbackofftolettheschedulerbelessaggre
ssive">Using backoff to let the scheduler be less aggressive</h3><p><strong>Available as of Camel 2.12</strong></p><p>The scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> is by default static by using the same poll frequency whether or not there is messages to pickup or not. From Camel 2.12 onwards you can configure the scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> to be more dynamic by using backoff. This allows the scheduler to skip N number of polls when it becomes idle, or there has been X number of errors in a row. See more details in the table above for the <code>backoffXXX</code> options.</p><p>For example to let a FTP consumer backoff if its becoming idle for a while you can do:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+</div></div><h4 id="BookPatternAppendix-Timerbasedpollingconsumer">Timer based polling consumer</h4><p>In this sample we use a <a shape="rect" href="timer.html">Timer</a> to schedule a route to be started every 5th second and invoke our bean <strong>MyCoolBean</strong> where we implement the business logic for the <a shape="rect" href="polling-consumer.html">Polling Consumer</a>. Here we want to consume all messages from a JMS queue, process the message and send them to the next queue.</p><p>First we setup our route as:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="brush: java; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[
+MyCoolBean cool = new MyCoolBean();
+cool.setProducer(template);
+cool.setConsumer(consumer);
+
+from("timer://foo?period=5000").bean(cool, "someBusinessLogic");
+
+from("activemq:queue.foo").to("mock:result");
+]]></script>
+</div></div>And then we have out logic in our bean:<div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="brush: java; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[
+public static class MyCoolBean {
+
+ private int count;
+ private ConsumerTemplate consumer;
+ private ProducerTemplate producer;
+
+ public void setConsumer(ConsumerTemplate consumer) {
+ this.consumer = consumer;
+ }
+
+ public void setProducer(ProducerTemplate producer) {
+ this.producer = producer;
+ }
+
+ public void someBusinessLogic() {
+ // loop to empty queue
+ while (true) {
+ // receive the message from the queue, wait at most 3 sec
+ String msg = consumer.receiveBody("activemq:queue.inbox", 3000, String.class);
+ if (msg == null) {
+ // no more messages in queue
+ break;
+ }
+
+ // do something with body
+ msg = "Hello " + msg;
+
+ // send it to the next queue
+ producer.sendBodyAndHeader("activemq:queue.foo", msg, "number", count++);
+ }
+ }
+}
+]]></script>
+</div></div><h3 id="BookPatternAppendix-ScheduledPollComponents">Scheduled Poll Components</h3><p>Quite a few inbound Camel endpoints use a scheduled poll pattern to receive messages and push them through the Camel processing routes. That is to say externally from the client the endpoint appears to use an <a shape="rect" href="event-driven-consumer.html">Event Driven Consumer</a> but internally a scheduled poll is used to monitor some kind of state or resource and then fire message exchanges.</p><p>Since this a such a common pattern, polling components can extend the <a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a> base class which makes it simpler to implement this pattern.</p><p>There is also the <a shape="rect" href="quartz.html">Quartz Component</a> which provides scheduled delivery of messages using the Quartz enterprise scheduler.</p><p>For more detai
ls see:</p><ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/PollingConsumer.html">PollingConsumer</a></li><li>Scheduled Polling Components<ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a></li><li><a shape="rect" href="scheduler.html">Scheduler</a></li><li><a shape="rect" href="atom.html">Atom</a></li><li><a shape="rect" href="beanstalk.html">Beanstalk</a></li><li><a shape="rect" href="file2.html">File</a></li><li><a shape="rect" href="ftp2.html">FTP</a></li><li><a shape="rect" href="hbase.html">hbase</a></li><li><a shape="rect" href="ibatis.html">iBATIS</a></li><li><a shape="rect" href="jpa.html">JPA</a></li><li><a shape="rect" href="mail.html">Mail</a></li><li><a shape="rect" href="mybatis.html">MyBatis</a></li><li><a shape="rect" href="quartz.html">Quartz</a></li><li><a sh
ape="rect" href="snmp.html">SNMP</a></li><li><a shape="rect" href="aws-s3.html">AWS-S3</a></li><li><a shape="rect" href="aws-sqs.html">AWS-SQS</a></li></ul></li></ul><h3 id="BookPatternAppendix-ScheduledPollConsumerOptions">ScheduledPollConsumer Options</h3><p>The ScheduledPollConsumer supports the following options:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Option</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>pollStrategy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"> </td><td colspan="1" rowspan="1" class="confluenceTd"><p>A pluggable <code>org.apache.camel.PollingConsumerPollingStrategy</code> allowing you to provide your custom implementation to control error handling usually occ
urred during the <code>poll</code> operation <strong>before</strong> an <a shape="rect" href="exchange.html">Exchange</a> have been created and being routed in Camel. In other words the error occurred while the polling was gathering information, for instance access to a file network failed so Camel cannot access it to scan for files. The default implementation will log the caused exception at <code>WARN</code> level and ignore it.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>sendEmptyMessageWhenIdle</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>startScheduler</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</
code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Whether the scheduler should be auto started.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>initialDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the first poll starts.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>delay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>500</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the next poll.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>useFixedDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Controls if fixed delay or fixed rate is used. See <a shape="rect" class="external-link" href="http://java.sun.com/j2se/1.5.0/
docs/api/java/util/concurrent/ScheduledExecutorService.html" rel="nofollow">ScheduledExecutorService</a> in JDK for details. In <strong>Camel 2.7.x</strong> or older the default value is <code>false</code>. From <strong>Camel 2.8</strong> onwards the default value is <code>true</code>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>timeUnit</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TimeUnit.MILLISECONDS</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>time unit for <code>initialDelay</code> and <code>delay</code> options.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>runLoggingLevel</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TRACE</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.8:</strong> The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.</p><
/td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduledExecutorService</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10:</strong> Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool. This option allows you to share a thread pool among multiple consumers.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>greedy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10.6/2.11.1:</strong> If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler</code></p></td><td colspan="1" row
span="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> Allow to plugin a custom <code>org.apache.camel.spi.ScheduledPollConsumerScheduler</code> to use as the scheduler for firing when the polling consumer runs. The default implementation uses the <code>ScheduledExecutorService</code> and there is a <a shape="rect" href="quartz2.html">Quartz2</a>, and <a shape="rect" href="spring.html">Spring</a> based which supports CRON expressions. <strong>Notice:</strong> If using a custom scheduler then the options for <code>initialDelay</code>, <code>useFixedDelay</code>, <code>timeUnit</code>, and <code>scheduledExecutorService</code> may not be in use. Use the text <code>quartz2</code> to refer to use the <a shape="rect" href="quartz2.html">Quartz2</a> scheduler; and use the text <code>spring</code> to use the <a shape="rect" href="spring.html">Spring</a> based; and use the text <code>#myScheduler</code> to
refer to a custom scheduler by its id in the <a shape="rect" href="registry.html">Registry</a>. See <a shape="rect" href="quartz2.html">Quartz2</a> page for an example.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler.xxx</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To configure additional properties when using a custom <code>scheduler</code> or any of the <a shape="rect" href="quartz2.html">Quartz2</a>, <a shape="rect" href="spring.html">Spring</a> based scheduler.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffMultiplier</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To let the scheduled polling consumer backoff if there has been a number of subsequent idles/erro
rs in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then <code>backoffIdleThreshold</code> and/or <code>backoffErrorThreshold</code> must also be configured.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffIdleThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent idle polls that should happen before the <code>backoffMultipler</code> should kick-in.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffErrorThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent error polls (failed due some error) that should happen before th
e <code>backoffMultipler</code> should kick-in.</p></td></tr></tbody></table></div></div><h3 id="BookPatternAppendix-Usingbackofftolettheschedulerbelessaggressive">Using backoff to let the scheduler be less aggressive</h3><p><strong>Available as of Camel 2.12</strong></p><p>The scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> is by default static by using the same poll frequency whether or not there is messages to pickup or not. From Camel 2.12 onwards you can configure the scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> to be more dynamic by using backoff. This allows the scheduler to skip N number of polls when it becomes idle, or there has been X number of errors in a row. See more details in the table above for the <code>backoffXXX</code> options.</p><p>For example to let a FTP consumer backoff if its becoming idle for a while you can do:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panel
Content pdl">
<script class="brush: java; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[ from("ftp://myserver?username=foo&passowrd=secret?delete=true&delay=5s&backoffMultiplier=6&backoffIdleThreshold=5")
.to("bean:processFile");
]]></script>
Modified: websites/production/camel/content/cache/main.pageCache
==============================================================================
Binary files - no diff available.
Modified: websites/production/camel/content/polling-consumer.html
==============================================================================
--- websites/production/camel/content/polling-consumer.html (original)
+++ websites/production/camel/content/polling-consumer.html Tue Sep 22 19:20:06 2015
@@ -157,7 +157,52 @@ public class SpringConsumerTemplateTest
}
]]></script>
-</div></div><h4 id="PollingConsumer-Timerbasedpollingconsumer">Timer based polling consumer</h4><p>In this sample we use a <a shape="rect" href="timer.html">Timer</a> to schedule a route to be started every 5th second and invoke our bean <strong>MyCoolBean</strong> where we implement the business logic for the <a shape="rect" href="polling-consumer.html">Polling Consumer</a>. Here we want to consume all messages from a JMS queue, process the message and send them to the next queue.</p><p>First we setup our route as:</p><div class="error"><span class="error">Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20</span> </div>And then we have out logic in our bean:<div class="error"><span class="error">Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20</span> </div><h3 id="PollingConsumer-ScheduledPollComponents">Scheduled Poll Components</h3><p>Quite a few inbound Camel endpoints use a scheduled poll pattern to
receive messages and push them through the Camel processing routes. That is to say externally from the client the endpoint appears to use an <a shape="rect" href="event-driven-consumer.html">Event Driven Consumer</a> but internally a scheduled poll is used to monitor some kind of state or resource and then fire message exchanges.</p><p>Since this a such a common pattern, polling components can extend the <a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a> base class which makes it simpler to implement this pattern.</p><p>There is also the <a shape="rect" href="quartz.html">Quartz Component</a> which provides scheduled delivery of messages using the Quartz enterprise scheduler.</p><p>For more details see:</p><ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/PollingConsumer.html">Pollin
gConsumer</a></li><li>Scheduled Polling Components<ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a></li><li><a shape="rect" href="scheduler.html">Scheduler</a></li><li><a shape="rect" href="atom.html">Atom</a></li><li><a shape="rect" href="beanstalk.html">Beanstalk</a></li><li><a shape="rect" href="file2.html">File</a></li><li><a shape="rect" href="ftp2.html">FTP</a></li><li><a shape="rect" href="hbase.html">hbase</a></li><li><a shape="rect" href="ibatis.html">iBATIS</a></li><li><a shape="rect" href="jpa.html">JPA</a></li><li><a shape="rect" href="mail.html">Mail</a></li><li><a shape="rect" href="mybatis.html">MyBatis</a></li><li><a shape="rect" href="quartz.html">Quartz</a></li><li><a shape="rect" href="snmp.html">SNMP</a></li><li><a shape="rect" href="aws-s3.html">AWS-S3</a></li><li><a shape="rect" href="aws-sqs.html">AWS-SQS</a></li></ul></li></ul
><h3 id="PollingConsumer-ScheduledPollConsumerOptions">ScheduledPollConsumer Options</h3><p>The ScheduledPollConsumer supports the following options:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Option</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>pollStrategy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"> </td><td colspan="1" rowspan="1" class="confluenceTd"><p>A pluggable <code>org.apache.camel.PollingConsumerPollingStrategy</code> allowing you to provide your custom implementation to control error handling usually occurred during the <code>poll</code> operation <strong>before</strong> an <a shape="rect" href="exchange.html">Exchange</a> have been created and being routed in Camel. In
other words the error occurred while the polling was gathering information, for instance access to a file network failed so Camel cannot access it to scan for files. The default implementation will log the caused exception at <code>WARN</code> level and ignore it.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>sendEmptyMessageWhenIdle</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>startScheduler</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Whether the scheduler should be auto started.</p></td></tr><tr><td colspan="1" rowspan="1" class="confl
uenceTd"><p><code>initialDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the first poll starts.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>delay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>500</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the next poll.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>useFixedDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Controls if fixed delay or fixed rate is used. See <a shape="rect" class="external-link" href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/ScheduledExecutorService.html" rel="nofollow">ScheduledExecutorService</a> in JDK for details. In <strong>Camel 2.7.x</strong> or older the
default value is <code>false</code>. From <strong>Camel 2.8</strong> onwards the default value is <code>true</code>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>timeUnit</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TimeUnit.MILLISECONDS</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>time unit for <code>initialDelay</code> and <code>delay</code> options.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>runLoggingLevel</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TRACE</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.8:</strong> The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduledExecutorService</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>
null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10:</strong> Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool. This option allows you to share a thread pool among multiple consumers.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>greedy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10.6/2.11.1:</strong> If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> Allow to plugin a custom <cod
e>org.apache.camel.spi.ScheduledPollConsumerScheduler</code> to use as the scheduler for firing when the polling consumer runs. The default implementation uses the <code>ScheduledExecutorService</code> and there is a <a shape="rect" href="quartz2.html">Quartz2</a>, and <a shape="rect" href="spring.html">Spring</a> based which supports CRON expressions. <strong>Notice:</strong> If using a custom scheduler then the options for <code>initialDelay</code>, <code>useFixedDelay</code>, <code>timeUnit</code>, and <code>scheduledExecutorService</code> may not be in use. Use the text <code>quartz2</code> to refer to use the <a shape="rect" href="quartz2.html">Quartz2</a> scheduler; and use the text <code>spring</code> to use the <a shape="rect" href="spring.html">Spring</a> based; and use the text <code>#myScheduler</code> to refer to a custom scheduler by its id in the <a shape="rect" href="registry.html">Registry</a>. See <a shape="rect" href="quartz2.html">Quartz2</a> page for an example.<
/p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler.xxx</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To configure additional properties when using a custom <code>scheduler</code> or any of the <a shape="rect" href="quartz2.html">Quartz2</a>, <a shape="rect" href="spring.html">Spring</a> based scheduler.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffMultiplier</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then <code>bac
koffIdleThreshold</code> and/or <code>backoffErrorThreshold</code> must also be configured.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffIdleThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent idle polls that should happen before the <code>backoffMultipler</code> should kick-in.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffErrorThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent error polls (failed due some error) that should happen before the <code>backoffMultipler</code> should kick-in.</p></td></tr></tbody></table></div></div><h3 id="PollingConsumer-Usingbackofftolettheschedulerbelessaggressive">Using bac
koff to let the scheduler be less aggressive</h3><p><strong>Available as of Camel 2.12</strong></p><p>The scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> is by default static by using the same poll frequency whether or not there is messages to pickup or not. From Camel 2.12 onwards you can configure the scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> to be more dynamic by using backoff. This allows the scheduler to skip N number of polls when it becomes idle, or there has been X number of errors in a row. See more details in the table above for the <code>backoffXXX</code> options.</p><p>For example to let a FTP consumer backoff if its becoming idle for a while you can do:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+</div></div><h4 id="PollingConsumer-Timerbasedpollingconsumer">Timer based polling consumer</h4><p>In this sample we use a <a shape="rect" href="timer.html">Timer</a> to schedule a route to be started every 5th second and invoke our bean <strong>MyCoolBean</strong> where we implement the business logic for the <a shape="rect" href="polling-consumer.html">Polling Consumer</a>. Here we want to consume all messages from a JMS queue, process the message and send them to the next queue.</p><p>First we setup our route as:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="brush: java; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[
+MyCoolBean cool = new MyCoolBean();
+cool.setProducer(template);
+cool.setConsumer(consumer);
+
+from("timer://foo?period=5000").bean(cool, "someBusinessLogic");
+
+from("activemq:queue.foo").to("mock:result");
+]]></script>
+</div></div>And then we have out logic in our bean:<div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="brush: java; gutter: false; theme: Default" type="syntaxhighlighter"><![CDATA[
+public static class MyCoolBean {
+
+ private int count;
+ private ConsumerTemplate consumer;
+ private ProducerTemplate producer;
+
+ public void setConsumer(ConsumerTemplate consumer) {
+ this.consumer = consumer;
+ }
+
+ public void setProducer(ProducerTemplate producer) {
+ this.producer = producer;
+ }
+
+ public void someBusinessLogic() {
+ // loop to empty queue
+ while (true) {
+ // receive the message from the queue, wait at most 3 sec
+ String msg = consumer.receiveBody("activemq:queue.inbox", 3000, String.class);
+ if (msg == null) {
+ // no more messages in queue
+ break;
+ }
+
+ // do something with body
+ msg = "Hello " + msg;
+
+ // send it to the next queue
+ producer.sendBodyAndHeader("activemq:queue.foo", msg, "number", count++);
+ }
+ }
+}
+]]></script>
+</div></div><h3 id="PollingConsumer-ScheduledPollComponents">Scheduled Poll Components</h3><p>Quite a few inbound Camel endpoints use a scheduled poll pattern to receive messages and push them through the Camel processing routes. That is to say externally from the client the endpoint appears to use an <a shape="rect" href="event-driven-consumer.html">Event Driven Consumer</a> but internally a scheduled poll is used to monitor some kind of state or resource and then fire message exchanges.</p><p>Since this a such a common pattern, polling components can extend the <a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a> base class which makes it simpler to implement this pattern.</p><p>There is also the <a shape="rect" href="quartz.html">Quartz Component</a> which provides scheduled delivery of messages using the Quartz enterprise scheduler.</p><p>For more details s
ee:</p><ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/PollingConsumer.html">PollingConsumer</a></li><li>Scheduled Polling Components<ul><li><a shape="rect" class="external-link" href="http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/impl/ScheduledPollConsumer.html">ScheduledPollConsumer</a></li><li><a shape="rect" href="scheduler.html">Scheduler</a></li><li><a shape="rect" href="atom.html">Atom</a></li><li><a shape="rect" href="beanstalk.html">Beanstalk</a></li><li><a shape="rect" href="file2.html">File</a></li><li><a shape="rect" href="ftp2.html">FTP</a></li><li><a shape="rect" href="hbase.html">hbase</a></li><li><a shape="rect" href="ibatis.html">iBATIS</a></li><li><a shape="rect" href="jpa.html">JPA</a></li><li><a shape="rect" href="mail.html">Mail</a></li><li><a shape="rect" href="mybatis.html">MyBatis</a></li><li><a shape="rect" href="quartz.html">Quartz</a></li><li><a shape=
"rect" href="snmp.html">SNMP</a></li><li><a shape="rect" href="aws-s3.html">AWS-S3</a></li><li><a shape="rect" href="aws-sqs.html">AWS-SQS</a></li></ul></li></ul><h3 id="PollingConsumer-ScheduledPollConsumerOptions">ScheduledPollConsumer Options</h3><p>The ScheduledPollConsumer supports the following options:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Option</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>pollStrategy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"> </td><td colspan="1" rowspan="1" class="confluenceTd"><p>A pluggable <code>org.apache.camel.PollingConsumerPollingStrategy</code> allowing you to provide your custom implementation to control error handling usually occurred du
ring the <code>poll</code> operation <strong>before</strong> an <a shape="rect" href="exchange.html">Exchange</a> have been created and being routed in Camel. In other words the error occurred while the polling was gathering information, for instance access to a file network failed so Camel cannot access it to scan for files. The default implementation will log the caused exception at <code>WARN</code> level and ignore it.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>sendEmptyMessageWhenIdle</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>startScheduler</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p
></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Whether the scheduler should be auto started.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>initialDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the first poll starts.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>delay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>500</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Milliseconds before the next poll.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>useFixedDelay</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Controls if fixed delay or fixed rate is used. See <a shape="rect" class="external-link" href="http://java.sun.com/j2se/1.5.0/docs/api
/java/util/concurrent/ScheduledExecutorService.html" rel="nofollow">ScheduledExecutorService</a> in JDK for details. In <strong>Camel 2.7.x</strong> or older the default value is <code>false</code>. From <strong>Camel 2.8</strong> onwards the default value is <code>true</code>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>timeUnit</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TimeUnit.MILLISECONDS</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>time unit for <code>initialDelay</code> and <code>delay</code> options.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>runLoggingLevel</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>TRACE</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.8:</strong> The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.</p></td></tr
><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduledExecutorService</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10:</strong> Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool. This option allows you to share a thread pool among multiple consumers.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>greedy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.10.6/2.11.1:</strong> If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> Allow to plugin a custom <code>org.apache.camel.spi.ScheduledPollConsumerScheduler</code> to use as the scheduler for firing when the polling consumer runs. The default implementation uses the <code>ScheduledExecutorService</code> and there is a <a shape="rect" href="quartz2.html">Quartz2</a>, and <a shape="rect" href="spring.html">Spring</a> based which supports CRON expressions. <strong>Notice:</strong> If using a custom scheduler then the options for <code>initialDelay</code>, <code>useFixedDelay</code>, <code>timeUnit</code>, and <code>scheduledExecutorService</code> may not be in use. Use the text <code>quartz2</code> to refer to use the <a shape="rect" href="quartz2.html">Quartz2</a> scheduler; and use the text <code>spring</code> to use the <a shape="rect" href="spring.html">Spring</a> based; and use the text <code>#myScheduler</code> to refer to
a custom scheduler by its id in the <a shape="rect" href="registry.html">Registry</a>. See <a shape="rect" href="quartz2.html">Quartz2</a> page for an example.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>scheduler.xxx</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To configure additional properties when using a custom <code>scheduler</code> or any of the <a shape="rect" href="quartz2.html">Quartz2</a>, <a shape="rect" href="spring.html">Spring</a> based scheduler.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffMultiplier</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a
row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then <code>backoffIdleThreshold</code> and/or <code>backoffErrorThreshold</code> must also be configured.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffIdleThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent idle polls that should happen before the <code>backoffMultipler</code> should kick-in.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>backoffErrorThreshold</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>0</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> The number of subsequent error polls (failed due some error) that should happen before the <code>
backoffMultipler</code> should kick-in.</p></td></tr></tbody></table></div></div><h3 id="PollingConsumer-Usingbackofftolettheschedulerbelessaggressive">Using backoff to let the scheduler be less aggressive</h3><p><strong>Available as of Camel 2.12</strong></p><p>The scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> is by default static by using the same poll frequency whether or not there is messages to pickup or not. From Camel 2.12 onwards you can configure the scheduled <a shape="rect" href="polling-consumer.html">Polling Consumer</a> to be more dynamic by using backoff. This allows the scheduler to skip N number of polls when it becomes idle, or there has been X number of errors in a row. See more details in the table above for the <code>backoffXXX</code> options.</p><p>For example to let a FTP consumer backoff if its becoming idle for a while you can do:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl"
>
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